The present invention relates to a control system for a longwall support having a plurality of hydraulically operated supports (mining shields).
A prior longwall control system of this general kind is disclosed in DE P 42 02 246.0 (Ti 9102) and U.S. Pat. No. 5,234,256, which are both incorporated herein by reference. In this prior case, the mining shields are adapted for automatic or manual rearrangement in the sense of robbing, advancing, and setting as a function of the position of the mining machine (cutters or plows).
This prior longwall control system has the disadvantage that its operation, be it for releasing functions, operational sequences or operating conditions, or be it for checking and observing the operability, exposes the operating person (operator) to safety risks. Likewise, the inspection of operability or operating conditions by one person is always subject to a risk of error, which is even intensified due to the difficult conditions in underground mining. This results again in hazards for a safe support of the longwall by incorrect readouts and wrong controls.
It is accordingly an object of the present invention to avoid these disadvantages and to equip the control system such that is operated free of wear and trouble, and yet is robust and reliable.
The present invention solves the above and other problems by providing a longwall control system for controlling a longwall support and facilitating the remote inspection of the longwall support. The longwall support comprises a plurality of hydraulically operated supports (mining shields), and a plurality of shield control devices respectively associated with the supports for rearranging the supports in the sense of robbing, advancing, and setting. The longwall control system further comprises detection devices for detecting inspection values associated with the operating parameters of the shield control devices. The longwall control system also comprises a hand-operated device. The hand-operated device comprises signaling devices, such as a readout or display. Long-distance transmission devices transmit the detected inspection values from the detection devices to the hand-operated device, and the signaling devices provide signals representative of the inspection values transmitted to the hand-operated device. This longwall control system has the advantage that it permits checking the operating parameters without requiring a hazardous closeness of the inspecting person to the longwall support that is to be inspected. A visual inspection of the operating parameters is no longer needed.
For further improving the operational safety, a control device for activating the shield control devices is integrated into the hand-operated device and connects to the shield control devices via a control radio network for releasing functions and operating conditions respectively.
For transmitting the inspection values, a radio network can be used or a long-range transmission by optical transmitters and sensors, in particular for infrared radiation, can be used. The latter possibility makes it unnecessary to use a further radio frequency and to reserve it for inspecting purposes.
To avoid influences on the control of functions and operating sequences by transmitting the inspection values, an interlock is utilized. More specifically, the control radio network (for releasing the functions and operating conditions respectively) and the long-distance transmission devices (for transmitting the inspection values) are interlocked so that the control radio network is disconnected by connecting the long-distance transmission devices, and the long-distance transmission devices are disconnected by connecting the control radio network.
In accordance with another aspect of the present invention, the hand-operated device comprises an operating side; a plurality of operating keys, which are mounted on the operating side, for the functions and operating conditions respectively; and an inspection side facing away from the operating side and mounting the signaling devices. This aspect prevents operating errors and makes it visually clear to the operator whether he is in the controlling or in the inspecting mode.
In accordance with another aspect of the present invention, the hand-operated device is equipped to meet with the special conditions of use in underground mining. More specifically, the long-distance transmission device is turned on and the control radio network is turned off only when the operator turns the hand-operated device toward him, and when in this process the light of the operator""s head lamp falls on one or two diodes mounted on the inspection side of the hand-operated device.
In accordance with another safety-related aspect of the present invention, the long-distance transmission devices are blocked while light is simultaneously incident upon both of the diodes, and the long-distance transmission devices are connected and the control radio network is blocked while light is incident upon only one of the two diodes.
Another aspect of the present invention is operative so that it is not necessary for the operator of the hand-operated device to perform all steps of inspecting all elements of the longwall support. This aspect advantageously decreases the likelihood of the operator missing an inspection. To this end, the longwall control system recalls the individual inspection values according to a program, transmits them according to a predetermined sequence, and retransmits them to the individual signaling devices of the hand-operated device. The long-range transmission devices of the longwall control system comprise an associated transmitter, which is used for transmitting the inspection values of a plurality of detection devices and/or longwall supports. Likewise, in this instance, it is avoided that the correct and complete inspection of all functions or operating conditions that are to be inspected are left to the operator.
In accordance with another aspect of the present invention, each mining shield control device is associated to a transmitter, which connects to the detection devices of the longwall supports. The longwall control system is operative to ensure that before carrying out the controlling operations on a longwall support, the operator first performs the necessary and intended inspections thereof.
In accordance with another aspect of the present invention, the longwall control system is operative to ensure that an inspection relates to a certain longwall support. More specifically, the long-distance transmission devices are operative to be activated by a code that is unmistakably associated to the longwall support and can be generated and transmitted by means of the hand-operated device. Based on the applied code, the operator is able to determine whether a longwall support that is to be controlled has already been inspected.